par Schmitz, Guy ;Furrow, Stanley
Référence PCCP. Physical chemistry chemical physics, 14, page (5711-5717)
Publication Publié, 2012
Article révisé par les pairs
Résumé : The iodate reduction by hydrogen peroxide in acidic solutions is part of the Bray-Liebhafsky and Briggs-Rauscher oscillating reactions. At low hydrogen peroxide concentrations, typical of the Bray-Liebhafsky reaction, its rate law is - d[IO3¯]/dt = (k'R + k"R [H+]) [IO3¯][H2O2] with k'R = 1.310-7 (25°), 7.810-7 (39°), 1.410 5 M-1s-1 (60°) and k"R = 1.510-5 (25°), 6.210-5 (39°), 6.310-4 M-2s-1 (60°). It is explained by a non-radical mechanism. At high hydrogen peroxide concentrations, typical of the Briggs-Rauscher reaction, a new reaction pathway appears with a rate more than proportional to [H2O2]2 and nearly independent on [IO3¯] > 0.01 M. This pathway is inhibited by scavengers of free radicals. We suggest that it has a radical mechanism starting with IOH + H2O2 IOOH + H2O and IOOH + H2O2  IO. + H2O + HOO..